The passage of California Proposition 1A (2008) set in motion a complete reconstruction of the railroad between San Jose and San Francisco. This blog exists to discuss compatibility between HSR and Caltrain, integration issues, and the impact on adjoining communities.

06 February 2010

Prunings and Removals

Expanding and electrifying the peninsula rail corridor will certainly impact many trees that grow alongside the tracks. The issue was already studied in some depth by Caltrain, which hired a certified arborist in 2003 to produce a Tree Survey and Assessment (6 MB PDF file) for its electrification project EIR (separately from the HSR EIR). This assessment did not include the effect of expanding the width of the corridor from two to four tracks for the HSR project, but it offers some interesting observations:

There are an estimated 19,250 trees adjacent to the Caltrain right of way between San Francisco and Gilroy.

Approximately 1,727 trees (9% of the total) would be impacted by the two-track electrification project.

Most of the impacted trees grow on private property, which makes any pruning or removal subject to local tree ordinances. (Trees on railroad land are not subject to tree ordinances.)

The tree survey includes a detailed tree-by-tree assessment of some of the densest tree canopies along the rail corridor, such as Atherton and Burlingame. It also includes a mile-by-mile summary of vegetation intensity on each side of the corridor, graphed in the figure at right. 1 = generally clear, 2 = scattered or intermittent, and 3 = dense with long stretches of continuous canopy.

How does the situation change with four electrified tracks? While the corridor generally provides sufficient space for four tracks, many more trees would be impacted because electrified tracks would be moved closer to the edges of the right-of-way than envisioned in the tree survey, which only studied impacts from electrification of the two existing tracks. One would expect many more trees to be impacted by the proximity of high voltage wires.

The Vegetation Grief Index

One possible way to quantify the relative HSR impacts to trees along the rail corridor is to combine the vegetation intensity index with the corridor width from San Francisco to San Jose. It's an interesting exercise because more trees will be impacted where the corridor is narrow. Take the sum of the vegetation intensity on both sides of the corridor, subtract two (so that we don't count "generally clear" areas), and simply divide by the width of the corridor. This is the formula for a Vegetation Grief Index (VGI), which is highest when the corridor is narrow and the vegetation is dense. The result is shown at left.

Interestingly, the VGI exceeds 3 in those communities (such as Burlingame, Atherton, Menlo Park and Palo Alto) that are the most worried about the HSR project and have formed the Peninsula Cities Consortium to advocate for their concerns. More generally speaking, the VGI seems to be an excellent predictor of anti-HSR sentiment among residents.

That might suggest that a key position is missing from the Peninsula Rail Program: a full-time certified arborist.

But Morris, you and these cities are going to use any tactic you can to completely stop HSR coming up the penincula. Whether it be "about trees", or the biggist smoke screen "HSR done right", it's just a repeat of when BART tried to circle the bay in the 70's. These cities showed their true colors before and we must not forget what their true intentions are. "Not in my back yard".

The other important factor to keep in mind is the species of tree. A lot of the trees growing along the Menlo Park ROW are considered "invasive"- not every tree along the ROW is a future El Palo Alto. (You can see a summary of tree types in the tree survey in Clem's post.)

A project that removed invasive species and replaced them with more desirable trees is something that I think most of us would support, regardless of our positions on High Speed Rail, grade separations, or electrification.

The reason there are more trees in Burlington, Atherton, Menlo Park and Palo Alto is because those are the towns where there are residences next to the railroad right-of-way. I think it's more a case of vegetation growth being an excellent predictor of residences, and that in turn is a predictor of concerns about the HSR project. People generally don't bother to plant trees behind warehouses.

Clem: With a little imagination we could design a low profile Caltrain-HSR right-of-way structure in a shallow open cut that would minimize Caltrain sevice disruptions during construction, reduce capital and operation outlays currently being contemplated, and increase the likelyhood that real-estate entrepreneurs would prefer to site future tall buildings close to the final Caltrain-HSR right-of-way.

Cuts require a good amount of space on either side to construct. Then again, so do berms (though elevated structures don't). Besides, the height difference between the road and the rails is much larger if you have the rails on the bottom (perhaps as much as 10 feet more). For any "shallow" trench, you'd have to raise roads considerably to get over the tracks.

First step for controlling system costs is to to reduce system requirements consistant with the anticipated level of service. So divert freight trains south of Redwood city over a revived Dumbarton rail trestle. It would be in the Union Pacific's interest to agree since most of their Peninsula freight traffic's destinations are northeast of the Dumbarton Bridge rail link.

If subject to local ordinances, then local ordinances that prevent cutting or removal of the trees could block the project?

In the long run, there is no chance of that happening. But it might be worth a small delay at some point.

Of course, legal risks run both ways. The Caltrain survey notes that many of the trees are in poor condition and unstable. If the condition of a given tree is sufficiently poor, and it then falls onto the ROW, destroys the catenary, and disrupts service, the homeowner would of course be liable. Many homeowners would no doubt prefer to take up an offer of free removal of questionable trees and replacement with healthier native trees than to risk being liable for hundreds of thousands of dollars of damage during the next rainy season.

Or, you could try the whole delay and obstruct thing, perhaps get a bit of delay, and end up with a situation in which homeowners have to pay for their own abatement costs or risk liability in damage to public infrastructure.

@Bianca: good point. That makes an arborist an important interface with impacted residents.

@anon: local tree ordinances no doubt allow for the removal of trees that stand in the way of public utilities or threaten public safety. But the fact that many trees grow on private property means the process must be coordinated closely with each affected community; for example, the local tree ordinances may require replacement trees to be planted. My suggestion to hire an arborist would aim to minimize just the sort of conflict you envision.

The railroad isn't subject to the local ordinances. They will be cutting down trees that affect operations. Why would they plant new ones? So they can come back in 5 or 10 years and cut them down again?

Sorry, I meant replacement trees elsewhere more appropriate. And do note: if the tree grows on private property, it is subject to the local tree ordinance, period. No matter who wants to cut it down. Being cavalier about the railroad's supposed rights over private property is not going to win this project any more friends than it already has.

Adirondacker12800 said..."The railroad isn't subject to the local ordinances. They will be cutting down trees that affect operations. Why would they plant new ones? So they can come back in 5 or 10 years and cut them down again?"

Typically as an "environmental mitigation" measure, eg, in a configuration with a wall on one side facing a busy thoroughfare and a berm on the other side with a low wall facing a residential neighborhood, planting shrubbery against the base of the low wall and a well chosen variety of tree at the base of the berm would eliminate a perceived negative visual impact of the low wall.

Compared to some "environmental mitigation", paying some people to go around once a year and prune the trees and shrubbery could prove a bargain.

replanting thousands of trees elsewhere also requires some land to plant on... presumably in the same city where the trees were cut down from?

But, even at aht that, perhaps makes the city right, that wouldn't make the homeowner right. I think probably not safe to assume that you would cut down their canopy of trees against a back fence, and be able to move those same number of trees 10 feet farther into their yards - without material change in value of the property.

Why would they plant new ones? So they can come back in 5 or 10 years and cut them down again?

Many of the trees in question are tall Monterey Pines that are overmature and have relatively short lifespans. They could be replaced with something else that doesn't grow as tall, is more stable, and doesn't spread as much canopy.

Typically as an "environmental mitigation" measure, eg, in a configuration with a wall on one side facing a busy thoroughfare

They aren't whining about what's going to be on the artfully landscaped berm. They are whining about trees that are on the ROW or immediately next to it. A native shrub that thrives on the rich irrigated soil of the berm, yet never grows much wider or taller than ten feet, planted 15 feet from the fence defining the edge of the ROW isn't the problem. It's the mature trees planted so close to the fence that the homeowners can't fit the lawnmower between it's trunk and the fence.

Many of the trees in question are tall Monterey Pines that are overmature and have relatively short lifespans. They could be replaced with something else that doesn't grow as tall, is more stable, and doesn't spread as much canopy.

Many of them, whatever they are, are right at the fence line. Whatever they plant, assuming they plant anything at all, won't be right next to the fence. The new homeowner who orders up some of those fast growing Monterrey Pines in 2030 and plants them right next to the fence will have the parts that grow over the fence, chopped off.

if the tree grows on private property, it is subject to the local tree ordinance, period. No matter who wants to cut it down.

If it's going to interfere with the safe operation of the railroad and the town gets intransigent about their tree ordinances the judge is going to say the railroad is within it's rights to prune the parts that are trespassing onto it's ROW. So the homeowner's and the town's choice will be to have the railroad's arborist supervise an experienced crew in removing the tree or have the railroad's arborist supervise the experienced crew in pruning the tree so severely that it dies two years later. Anything new that grows onto the ROW will be chopped off.

Not that I've run the numbers, but I bet if you looked at the overall tree canopy of these impacted communities, it would be higher than it is in other ones. In other words, communities with a lot of trees along the corridor also have a lot of trees away from the corridor. This could be correlated with income, the age of housing stock and any other number of factors.

I'm not really adding anything to this particular topic, but I just wanted to say I really enjoy reading this blog. Thank you for taking the time to dig into Peninsula HSR issues in detail and to host a (relatively) civil forum. Keep up the good work!